Sure. But why? The YouTube channel for example is ALWAYS the account of the client. It's YOUR channel.
Further, the Content Materials we are given are always the property of the client, and once fully paid, all other Content Materials (such as photo shoot originals, graphics, etc.) that we generated for the client, are then the exclusive property of the client as well.
As explained above, a video with high subscriptions for example, will lose that exposure and popularity if moved.